The present disclosure relates to generally to acidizing operations relative to subterranean formations.
Treatment fluids can be used in a variety of subterranean treatment operations. Such treatment operations can include, without limitation, drilling operations, stimulation operations, production operations, remediation operations, sand control treatments, and the like. As used herein, the terms “treat,” “treatment,” “treating,” and grammatical equivalents thereof refer to any subterranean operation that uses a fluid in conjunction with achieving a desired function and/or for a desired purpose. Use of these terms does not imply any particular action by the treatment fluid or a component thereof, unless otherwise specified herein. More specific examples of illustrative treatment operations can include drilling operations, fracturing operations, gravel packing operations, acidizing operations, scale dissolution and removal operations, sand control operations, consolidation operations, and the like.
Acidizing operations may be performed to stimulate a subterranean formation to increase production of a hydrocarbon resource therefrom. An acidizing fluid (e.g., a treatment fluid comprising hydrochloric acid) may be used to dissolve an acid-soluble material in the subterranean formation (e.g., carbonates, silicates, and aluminosilicates). In the case of carbonate formations, the acidizing fluid may produce an interconnected network of conductive pathways known as wormholes. During production operations, the wormholes provide pathways for the hydrocarbons to move from the formation and into the wellbore.
However, as the temperature of the subterranean formation increases (e.g., above about 250° F.), hydrochloric acid may react with the formation more aggressively and, rather than forming wormholes through the formation, dissolve the full face of the formation. As such, the acidizing fluid may not penetrate as deeply into the formation to reach hydrocarbon reserves, which leads to less productive wells.
Additionally, at the elevated temperature, hydrochloric acid may corrode downhole tools and tubulars to a greater extent, which may require a costly and time-consuming operation to retrieve and replace the tool or tubular. Therefore, in higher-temperature acidizing operations, an alternative acidizing fluid may be needed.